add preliminary parsing and display of M17 metadata

csdr/module/__init__.py

@@ -118,8 +118,11 @@ class PopenModule(AutoStartModule, metaclass=ABCMeta):
     def getCommand(self):
         pass
 
+    def _getProcess(self):
+        return Popen(self.getCommand(), stdin=PIPE, stdout=PIPE)
+
     def start(self):
-        self.process = Popen(self.getCommand(), stdin=PIPE, stdout=PIPE)
+        self.process = self._getProcess()
         # resume in case the reader has been stop()ed before
         self.reader.resume()
         Thread(target=self.pump(self.reader.read, self.process.stdin.write)).start()

csdr/module/m17.py

@@ -1,8 +1,20 @@
 from csdr.module import PopenModule
 from pycsdr.types import Format
+from pycsdr.modules import Writer
+from subprocess import Popen, PIPE
+from threading import Thread
+
+import re
+import pickle
 
 
 class M17Module(PopenModule):
+    lsfRegex = re.compile("SRC: ([a-zA-Z0-9]+), DEST: ([a-zA-Z0-9]+)")
+
+    def __init__(self):
+        super().__init__()
+        self.metawriter = None
+
     def getInputFormat(self) -> Format:
         return Format.SHORT
 
@@ -10,4 +22,37 @@ class M17Module(PopenModule):
         return Format.SHORT
 
     def getCommand(self):
-        return ["m17-demod"]
+        return ["m17-demod", "-l"]
+
+    def _getProcess(self):
+        return Popen(self.getCommand(), stdin=PIPE, stdout=PIPE, stderr=PIPE)
+
+    def start(self):
+        super().start()
+        Thread(target=self._readOutput).start()
+
+    def _readOutput(self):
+        while True:
+            line = self.process.stderr.readline()
+            if not line:
+                break
+            self.parseOutput(line.decode())
+
+    def parseOutput(self, line):
+        if self.metawriter is None:
+            return
+        matches = self.lsfRegex.match(line)
+        msg = {"protocol": "M17"}
+        if matches:
+            # fake sync
+            msg["sync"] = "voice"
+            msg["source"] = matches.group(1)
+            msg["destination"] = matches.group(2)
+        elif line.startswith("EOS"):
+            pass
+        else:
+            return
+        self.metawriter.write(pickle.dumps(msg))
+
+    def setMetaWriter(self, writer: Writer) -> None:
+        self.metawriter = writer